The Intel Socket 3 is a processor socket with 237-pin holes in 19 by 19 rows, and ran at 3.3v and 5v. The Socket 3 socket was compatible with the Intel 486SX, 486DX, 486DX2, 486DX4, and OverDrive processors. To the right is an illustration of the Socket 3 socket.
This socket is not compatible with 3v processors and often was found on motherboards that had a coprocessor socket. Also, this socket cannot determine the voltage provided and must rely on a jumper that allows you to select either 3.3v or 5v.